Load engaging apparatus for lift trucks



A ril 2, 1963 FIG. I

LOAD ENGAGING APPARATUS FOR LIFT TRUCKS Filed June 6. 1960 5 SheetsSheet1 IN VEN TOR.

RUSSELL HASTINGS JR.

ATTORNEY April 1963 R. HASTINGS, JR 3,083,853

1.0m: ENGAGING APPARATUS FOR LIFT TRUCKS Filed June 6. 1960 5Sheets-Sheet 2 IN V EN TOR.

RUSSELL HASTINGS JR.

ATTORNEY A ril 2, 1963 R. HASTINGS, JR

LOAD ENGAGING APPARATUS FOR LIFT mucxs Filed June 6. 1960 5 Sheets-Sheet3 FIG. 4

INVENTOR.

RUSSELL HASTINGS JR. W

ATTORNEY April 2, 1963 R. HASTINGS, JR 3,033,853

LOAD ENGAGING APPARATUS FOR LIFT mucxs Filed June 6. 1960 5 Sheets-Sheet4 FIG. 5

INVENTOR. RUSSELL HASTINGS JR ATTORNEY April 2, 1963 R. HASTINGS, JR

LOAD ENGAGING APPARATUS FOR LIFT TRUCKS Filed June 6. 1960 5Sheets-Sheet 5 INVENTOR. RUSSELL HASTINGS JR.

ATTORNEY United States Patent 3,083,853 LOAD ENGAGING APPARATUS FOR LIFTTRUCKS Russell Hastings, Jr., Battle Creek, Mich., assignor to ClarkEquipment Company, a corporation of Michigan Filed June 6, 1960, Ser.No. 34,117 18 Claims. (Cl. 214-660) This invention relates to apparatusfor tilting elevatable load engaging means, and more particularly toapparatus for tilting the load engaging means of a lift truck having anupright mast with which the load engaging means is associated forvertical movement.

In certain types of elevating mast apparatus, such as is normallyassociated with lift trucks and the like, a problem arises concerninghow best to provide in an extremely limited space for tilting in avertical plane of the lifting fork or other load engaging means when thefork is associated with a non-tilting mast structure. Also, although themast structure may be tiltable, it may be found to be desirable toprovide tilting movement of the fork additional to that provided by themast structure.

My invention relates to improved apparatus for tilting in relativelylimited space load engaging means in the aforementioned association. Ithas been found to be particularly useful in lift trucks of a typegenerally known as narrow-aisle trucks in which the mast is fixed innon-tilting relationship to the chassis, so that any tilting of the forkmust be effected independently of tilting of the mast,

In carrying out the invention I provide in an elevatable load carriagefor mounting in a lifting mast a cranking means which is associated ineccentric pivotal relation to a guide roller of the carriage so thatrotation of the crank causes the carriage to be pivoted about avertically spaced pivot means to a tilted position. Such tiltingmovement occurs upon the initiation of lifting movement of the carriagein the mast when a load engaging means of the carriage is in engagementwith a load of predetermined mass which overcomes resilient meansnormally urging the carriage and load engaging means to a non-tiltedposition. When the load engaging means, hereinafter sometimes referredto as a fork or fork tines to simplify the expression, supports such asa load, the hoisting chain or cable normally associated with lift truckmast constructions functions to overcome the force of such resilientmeans to actuate the cranking means as aforesaid. In addition, aninclined plane arrangement is provided in the lifting mast which permitsthe carriage and fork to assume a reversely tilted position when it islowered in the mast to a position near the bottom end thereof.

It is an important object of the invention to provide generally improvedtilting apparatus which is operative in relatively limited space for theload engaging means of an elevator mechanism.

Another object of the invention is to provide apparatus for tiltingrearwardly the load engaging means of a lift truck only in the event ofa load being supported by the load engaging means.

It is a further object of the invention to provide fork tilt apparatusfor lift trucks or other elevator mechanism wherein means urges the loadengaging means toward a level position and is overcome upon initiationof lifting movement of the load engaging means under load to provide arearward tilting movement of the load engaging means.

It is a further object of the invention to provide means in the uprightmast of a lift truck which causes and elevatable load engaging meansassociated therewith to be tilted in a forward direction when it islocated adjacent the lower end of the mast.

Other objects, features and advantages of the present 3,083,853 PatentedApr. 2, 1963 "ice invention will appear in the detailed descriptionbelow when taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a side elevational view showing the general arrangement ofone type of industrial lift truck in which the present invention findsparticular utility;

FIGURE 2 is a perspective view of the fork carriage construction of thepresent invention;

FIGURE 3 is a rear view shown partially in section of the fork carriageof FIGURE 2;

FIGURE 4 is a side view in section taken along line 4--4 of FIGURE 5;

FIGURE 5 is a top view shown partly in section taken along a line suchas 55 of FIGURE 3 but with the load carriage assembly mounted in themast of the truck, the section being taken through opposite center sideportions of the carriage assembly and through the upright channels ofthe mast, and then extending upwardly and above the central hoist motorand sheave portion of the mast so as to illustrate the latter inelevational view;

FIGURES 6, 7, 8 and 9 are schematic ilustrations of a portion of theupright and carriage assembly with the latter being illustrated invarious attitudes of operation in the respective figures.

Referring now in detail to the drawings and first to FIGURE 1, the mainframe of a wheeled truck is generally in the form of a U-shape, theprojecting legs of which are spaced transversely apart. Each outriggerleg, one of which is shown, comprises a longitudinally extending channelconstruction 10 upon which is mounted a ground engaging wheel 12. Theopposite ends of the legs are secured together and the spacetherebetween is bridged by means of transverse frame members. A liftingmast or upright of generally known construction is illustrated atnumeral 14 and comprises broadly a pair of laterally spaced outer fixedchannel members 16, a pair of laterally spaced I-bearns 18 suitablynested as shown within the channel members for vertical telescopingmovement, a hydraulic hoist motor 20 (FIG. 5), and a carriage assembly22, including fork tines 24, which is mounted in a manner to bedescribed for vertical movement relative to members 18, the forkcarriage being connected to hoist motor 20 in known manner by means ofchain and sprocket mechanism.

The upright structure 14 is suitably connected by means of a pair ofrearwardly extending L-shaped brackets 26, only a portion of one ofwhich is illustrated, to the channel members 10 for longitudinalmovement relative thereto. Each member 26 is secured to a lower sideportion of one of channel members 16 and mounts the upright upon theadjacent channel member 10 by means of a pair of rollers locatedadjacent the opposite ends of each L-shaped bracket and in rollingabutment with inner and outer surfaces of the upper flange of eachchannel member 10. An upper one of such pairs of rollers is illustratedat numeral 28. The bracket members 26 may be associated with a worm gearmechanism, not shown, located within each channel member 10 so that asthe worm gears are rotated in one or the other directions the mast 14 isactuated longitudinally outwardly or inwardly of the legs, asillustrated in FIGURE 1. Suitable motor means and driving mechanism, notshown, are mounted within a main body portion 30 for driving the wormgear mechanisms, and thereby the mast construction. A pair ofdriving-steering wheels 32, one of which is shown, are controlled bymeans of a steering tiller 34, and a master truck contnol handle 36controls the operation of an electric drive motor 38 as well ascontnolling vertical movement of carriage assembly 22 in the mast 14. Acontrol lever 40 controls the operation in extension and retraction ofupright and carriage assembly 14 and 22, An operators ovcrhcad guardconstruction 42 is adapted to protect the drive from injury from fallingobjects.

The utility of the carriage assembly of the present invention is wellexemplified in the illustrated association with a lift truck of the typeshown in FIGURE 1, wherein the upright assembly 14 cannot be tilted outof a vertical position. However, it will be understood that the presentinvention is not intended to be restricted to use with any particulartype of industrial truck or other industrial vehicle, but may be usablein various associations.

The fork carriage assembly 22, as best shown in FIG- URES 2 and 3,comprises a pair of vertically spaced transverse plate members 50 and52, to the opposite ends of which is secured, as by welding, a pair oflaterally spaced L-shaped fork tines 24. A pair of rollers 54 is securedto the upper corner portions of tines 24 which, with the carriagemounted in upright 14, are adapted to abut the outer forward edgeportions 56 of inner movable upright I-beams 18. Rollers 54 are adaptedto cooperate during operation with a pair of transversely spaced cockedrollers 58 of the carriage assembly to prevent lateral twisting orrotational movement of the carriage assembly under the influence of anoff-center load on the fork tines 24. A similar upright construction tothat shown herein is fully disclosed in co-pending application SerialNo. 11l,070, filed May 18, 1961, in the names of Hastings and Backofen(common assignee).

A pair of laterally spaced and rearwardly extending carrier plates 60are secured to the rear surfaces of plates 50 and 52 and provideopenings in the upper ends thereof for the reception of a pair of shafts62 upon which are mounted outwardly of carrier plates 60 a pair of uppercarriage guide rollers 64. Adjacent the lower ends of the carrier plate60, which include recessed portions 66, are openings 68 for thereception of a pair of shaft members 70 upon which are formed inwardlyof carriage plates 60 a pair of crank members 72 having forwardlyextending portions 74. Each portion 74 is received in a slot 76 of abifurcated lower portion of each end portion 78 of a transverse springsupport and chain anchor member 80. Pin members 81 pivo-tally connectcrank end portions 74 with each bifurcated end portion of support andanchor member 80. Supported from the upper edge of support and anchormember 80 are the lower ends of a pair of compression springs 82 whichare secured to plate member 50 by a pair of spring adjustment studs 84and a pair of tubular members 86 which may be welded to plate 50. A rod88 extends through each spring and is secured at the lower end to member80, being slidably engaged with each stud 84 internally thereof. A pairof bifurcated chain anchors 90 are secured by pins 92 to the oppositeend portions of support and anchor member 80 and pro vide anchor pins 94for the reception of one end of each of a pair of lifting chain members96 which extend from said anchors upwardly for reaving over a pair oflaterally spaced sheaves or sprockets 97 and thence downwardly toconnect with fixed chain anchor members, not shown, which may be securedeither to a fixed portion of the upright 14 or which may be secured tothe lower end portion of the fixed cylinder hoist motor 20. Sprockets 97are secured in known manner to a crosshead 98 which extends laterallyoutwardly from opposite sides of the upper end of the piston rod ofhoist motor 20. Inner and outer upright supports 99 and 100 are securedto the rear sides of pairs of upright members 18 and 16, respectively,and piston rod guide support means 101 functions to guide the piston rodduring operation.

Each shaft member 70 includes a central internally splined opening 103(FIG. 3) engaging an externally splined shaft 102 to the outer ends ofwhich is securely mounted a rotatable and generally circular travellimit control member 104 having an upper projecting end 106, each ofwhich abuts along a flat forward surface thereof a stop block 108secured in predetermined position in each of recesses 66. A pair of stubshafts 110 is secured to the outer surfaces of movement limit members104 in spaced relation to the pivot shafts 102 for receiving the pair ofroller carriage guide rollers 58. Preferably the stub shafts 110 areformed to provide a slight forwardly cocked relation to a horizontalline transverse of the upright so that when rollers 58 are mountedthereon they assume a position relative to I-beams 18 as shown in FIG.5. Upper stub shafts 62 are formed to provide a slight reverse cockedrelation to a horizontal line transverse of the upright for receivingupper rollers 64, all as described in detail in the aforementionedco-pending application. The particular manner in which the carriageguide rollers 58 and 64 are cocked as aforesaid is not important to anunderstanding of the present invention, and straight or non-cockedrollers may be used with equal facility in the construction whichembodies the invention.

Preferably, the axis of stub shafts 110 is located a predetermineddistance vertically above the axis of shafts '70 and 102 so that pivotalmovement of crank members 72 and movement limiting members 104 about theaxis of shafts 102 causes a small horizontal arcuate movement of rollers58 with shafts 110 when the carriage assembly 22 is not mounted in theupright. Such movement occurs inasmuch as the axis of shafts 110 islocated in eccentric relation to the axis of shafts 102. Since members104 pivot about the axis of shafts 102 eccentrically connected shafts110 move slightly arcuately rearwardly upon counterclockwise movement ofcrank members 72 as viewed in FIGURE 4. The normal position of the lowerroller, crank and movement limiter assembly is illustrated in FIGURES 2,3 and 5, as well as in the solid and dotted line position of the partsin FIGURE 4. In this position compression springs 82 urge support andanchor member downwardly against any upward lifting force applied tochains 9-6 by hoist motor 20 when fork tines 24 do not support a load.Member 80 assumes a normal down position in which crank arms 72 arepivoted in a clockwise direction with shafts 70 and 102, as viewed inFIGURE 4, to the aforementioned position in which the vertical forwardsurfaces of projections 106 abut adjacent vertical surfaces of stopmembers 108. With the assembly so located, the downwardly directed forceof springs 82 is suflicient to support the weight of the unloadedassembly 22 and the vertical- 1y movable I-beams 18. Therefore, upwardlydirected movement of hoist motor 20 to first lift the carriage assemblyby means of chains 96 and then lift the carriage and the I-beams 18together, in known manner, does not overcome the downward force ofsprings 82. Thus, the lower roller and crank arm assemblies 58 and 72will remain in the position illustrated in which limit control members104 abut stop members 108 and in which fork tines 24 are preferablylocated in parallel relation to the floor or other supporting surfaces.

When the truck is moved adjacent a non-palletized load and the upright14 extended to the end of arms 10 to insert fork tines 24 under the loadfor lifting movement thereof in the upright 14, it is desirable that thefork tines be initially tilted forwardly so that the tips thereof touchthe floor, and that upon engaging the load the fork tines be tiltedslightly rearwardly of such normal position so that the load does nottend to move forwardly relative to the fork tines during maneuvering ofthe truck while carrying the load. Forward tilting of the fork andcarriage assembly is provided by means of a rearwardly inclined planesurface 116 formed in the lower flange portion of each I-beam 18, asbest illustrated in FIGURE 4. It will be appreciated, of course, thatthe weight of the load and/or carriage assembly 22 maintains at alltimes upper rollers 64 in rolling contact with the forward flangeportions of I-beams 18 and lower rollers 58 in rolling contact with therearward flange portions of the I-beams.

Therefore, as the carriage assembly is actuated downwardly in the lowerportion of the I-bearns, lower rollers 58 follow the contour of inclinedplane portion 116 which causes the carriage and fork assembly to tiltforwardly of a level position, thereby facilitating entry of the forktines beneath a non-palletized load. Raising the carriage assembly abovethe inclined plane portion in I-beams 18 returns the fork and carriageassembly to a position parallel to the truck supporting surface when thecrank and lower roller assembly 72 and 58 is in the solid line positionof FIGURE 4.

Upon engagement and initial lifting movement by hoist motor 20 andchains 96 of a load on the fork tines 24 sufficient to overcome thedownward force of springs 82, the opposing lifting force of the chainscauses compression of springs 82 and actuates support and anchor member80 upwardly which carries end portions 74 of crank members 72 therewithin counterclockwise rotation (FIG. 4) about the axis of the crankmembers until end portions 78 of member 80 abut stop blocks 118 whichare secured to the inner opposed surfaces of carriage plates 60. Suchpivotal movement of the crank members 72 and shafts 102 causes likepivotal movement of limit control members 104 away from stop blocks 108to the chained line position thereof illustrated in FIGURE 4, which inturn causes pivotal movement of eccentrically mounted lower rollers 58from the solid to the chained line position thereof.

As pointed out hereinabove, lower rollers 58 tend upon suchcounterclockwise motion of crank members 72 to move arcuately rearwardlyas a result of the eccentric mounting thereof in respect of the axes ofshafts 102. However, when the carriage assembly is mounted in theupright, rollers 58 being in contiuous abutment with the rearward innerflange portion of I-beams 18 necessarily follow the contour of theflange portion. Except for the provision of the inclined plane portion116 at the lower end of the I-beams, the inner surface of said flangeportion is vertical so that the lower rollers are forced to moveslightly downwardly in a vertical direction, not arcuately rearwardly.This downward movement of the lower rollers is represented in FIGURE 4by the illustrated downward shift of the roller shaft 110 which mountsthe roller on limit control member 104, the axis of the shaft 110 movingfrom point 120 to point 122. Such movement forces the entire carriageand fork assembly outwardly of the upright in a counterclockwisedirection about the axis of upper roller shafts 62, which remains inessentially fixed position, so that as the crank members 72 are actuatedin a counterclockwise direction against springs 82 the axes of shafts 70and 102 are moved essentially horizontally forwardly from the locationindicated at point 124 to the location indicated at point 126.

It will be understood, of course, that for any given design theparticular relationship or distance between the axes of the upper andlower rollers and between the axes of the lower rollers and the crankarms may be varied to provide dilferent fork carriage tiltingcharacteristics as desired, that illustrated in the figures being merelyrepresentative. It will also be understood, however, that in any givendesign the distance between the axis of the upper rollers 64 and theaxis of the crank arms 72 will remain constant at all times inasmuch asboth the rollers and the crank arms are mounted in carrier plates 60,and, likewise, the distance between the axes of lower rollers 58 and theaxis of the crank arms will remain fixed at all times irrespective ofthe position of the crank arms and rollers, whether in fork tilt ornon-tilt position. It has been found that approximately 2 forward tiltis adequate with the carriage assembly in the lowered position, and thatthe provision of approximately 3 rearward tilting movement of thecarriage assembly coincident with full cranking action of cranks 72 isadequate to offset the clastic deflection of the fork tines under heavyload and to prevent slippage of the load relative to the forks duringmaneuvering of the truck. Of course, if with the carriage assembly in alowered position, and therefore in a 2 forward tilt position inaccordance with the foregoing example, the load is engaged and initiallylifted by chains 96 to actuate crank arms 72 until members 78 contactstop blocks 118, the total rearward tilting movement effected thereby insuch position will be 1". On the other hand, with the fork carriagelifted above the inclined plane portion 116 such rearward tilt will be 3in accordance with the foregoing example. These results are illustratedsomewhat schematically in FIGURES 6, 7, 8 and 9. FIGURE 6 illustratesthe major component parts of the fork carriage assembly in associationwith the lower portion of the one I-beam of the upright when theassembly i in normal position preparatory to engaging a load, in whichposition the fork is tilted slightly forwardly, 2 in the foregoingexample, of a level position relative to the floor line. FIGURE 7illustrates the aforesaid 1 rearward tilt position of the fork andcarriage assembly with crank arms 72 fully actuated. FIGURE 8illustrates the normal level position of the fork and carriage assemblywith the assembly raised above the inclined plane portion 116 andpreparatory to engaging a load, and FIGURE 9 illustrates the full 3rearward tilt position of the fork and carriage assembly.

From the foregoing it will be appreciated that I have provided in a forktruck having a non-tilting mast, a fork carriage assembly which includesmechanism for tilting same rearwardly of a level position uponengagement with the load, while providing a normal level fork positionwhen the fork is out of engagement with the load whether or not I-beams18 and/or carriage assembly 22 is lifted by chains 96 to any givenelevation in the upright 14. In addition, inner movable upright sections18 are formed to provide for the forward tilting of the fork andcarriage assembly when the latter is located in the lower portion of theupright. Of course, it will be recognized that inclined plane portions116 can be extended upwardly to any desired elevation relative to thelength of I-beams 18, depending upon the desired slope and the thicknessof the of the flanged sections of the I-beams. If, for example, theinclined plane portion extended throughout the length of the I-beams itwill be apparent that a slight forward tilt would exist throughoutelevation of the unloaded carriage assembly, although this has not beenfound to be desirable. It has been found to be most desirable to provideforward tilt only at the lower end of the upright, in which positionsome difficulty would otherwise be encountered in projecting the forkunder floor supported nopalletized loads, and to limit the length of theinclined portion such that the fork tines will assume the rearward tiltposition of FIGURE 9, under predetermined load, when the fork tines havebeen elevated to a height at which the mast 14 with its load can beretracted above the outrigger legs 10 for transporting the load.

The invention as illustrated and described in the single embodimenthereof discloses the preferred construction, although I do not intend tobe limited to any such construction.

Now, while I have shown and described what I believe to be a preferredembodiment of my present invention, it will be understood that variousrearrangements and modifications in design, parts and construction maybe made therein without departing from the spirit and scope of myinvention.

I claim:

1. A load carrier for lift trucks comprising load support means, a pairof transversely spaced members secured to the load support means, acrank arm mounted in each said member for pivotal movement relativethereto, means interconnecting said crank arms, resilient means securedto the load support means and connected to said interconnecting meansfor urging the crank arms in pivotal movement in a direction away fromthe connection of the resilient means to the load support means, andload lifting means operatively connected to the crank arms for liftingthe load carrier and pivoting the crank arms in a direction opposed tothe urging of the resilient means when the load carrier supports apredetermined load.

2. A load carrier for lift trucks comprising load support means, meansextending transversely of and secured to the load support means, a crankarm mounted in the transverse means for pivotal movement relativethereto, resilient means operatively connected to the crank arm andsecured to the load support means, roller means operatively connected tothe crank arm and disposed on the opposite side of the transverse meanshaving an axis of rotation which is eccentric in relation to the axis ofrotation of the crank arm, and load lifting means operatively connectedto the crank arm for lifting the load carrier and pivoting the crank armin opposition to the resilient means, such pivotal movement of the crankarm causing the axis of the roller means to shift its position relativeto the axis of the crank arm.

3. A load carrier comprising generally L-shaped load support means, apair of transversely spaced carriage members extending rearwardly of thesupport means, first roller means mounted in the upper and outer portionof each carriage member, pivotable crank means rotatably mounted in thelower inner portion of each carriage member, second roller means mountedin the lower outer portion of each carriage member and operativelysecured for movement with the crank means in eccentric relation thereto,said crank means being interconnected by means transverse to thecarriage members, means connected to the interconnecting means forurging the crank means in one direction, and lifting means operativelyconnected to the crank means for pivoting same in a direction opposingthe latter means, such pivotal movement of the crank means causing adisplacement in the location of the lower roller means.

4. A load carrier as claimed in claim 3 wherein move ment limiting meansis associated with said crank means for limiting pivotal movementthereof in one direction.

5. A load carrier as claimed in claim 3 wherein the radii between theaxes of said upper roller means and said crank means is constant, theradii between the axes of said lower roller means and said crank meansis constant, and pivotal movement of said crank means causes the radiibetween the axes of asid upper and lower roller means to vary.

6. A load carrier as claimed in claim 3 wherein rotatable movementlimiting means is mounted for pivotal movement with said crank means,said lower roller means being mounted for pivotal movement with saidmovement limiting means and having an axis of rotation displaced fromthe axis of rotation of said crank means, pivotal movement of said crankmeans causing arcuate movement of said lower roller means with pivotalmovement of said movement limiting means about the axis of said crankmeans.

7. An upright mast and load carrier assembly for use in lift truckscomprising a pair of laterally spaced upright mast members havingopposed channel portions inwardly thereof, load support means supportedforwardly of the mast members and having a pair of laterally spacedrearwardly extending carrier members, upper and lower roller meansmounted outwardly of each carrier memher for engagement in said channelportions supporting the load support means therein, a pair of inwardlydisposed crank means mounted for pivotal movement in the lower innerportions of the carrier members, means interconnecting said crank means,resilient means supported from the interconnecting means at one end andsecured to the load support means at the opposite end for urging saidcrank means in downward pivotal movement, load carrier lifting meansassociated with the upright mast and operatively connected to the crankmeans and resilient means for actuating the load support meansvertically in the upright mast, said lifting means effecting upwardpivotal movement of the crank means in opposition to the resilient meansunder a predetermined load supported by the load support means.

8. An assembly as claimed in claim 7 wherein said lower roller means aremounted in eccentric relation to the crank means and for movement uponactuation of the crank means whereby to actuate the load support meansin outward pivotal movement about a pivot axis associated with the upperroller means.

9. An assembly as claimed in claim 8 wherein such movement of the lowerroller means reacts against a portion of the upright mast such that thecrank means and load support means is caused to swing somewhat forwardlyof the upright mast about the axis of the upper roller means.

10. A load carrier and upright mast assembly for lift trucks comprisinga pair of laterally spaced movable upright members supported from thetruck, load support means supported forwardly of the upright members,upper and lower roller means connecting the load support means to theupright members for relative vertical movement, a pair of pivotablemembers connected to the load support means adjacent one of said rollermeans, a transverse member interconnecting said pivotable members, meansurging the interconnecting means and pivotable members in one directionrelative to the load support means in said pair of upright members, saidurging means to the interconnecting means for raising the load supportmeans in said pair of upright members, said urging means beingconstructed to support the weight of the load carrier during elevatingmovement thereof by the motor means.

11. An assembly as claimed in claim 10 wherein said load support meansis caused to tilt to a rearward inclination upon lifting movementthereof under predetermined load, such rearward tilting movement beingeffected by actuation of the pivotable members against the urging meansin cooperation with a shift in location of the said one roller means.

12. An assembly as claimed in claim 11 wherein said one roller means ismounted for movement relative to the pivotable members in a manner toeffect movement in translation of the pivotable members with pivotalmovement of the load support means about the axis of the other rollermeans.

13. A load carrier and upright mast assembly for lift trucks comprisinga pair of laterally spaced upright members, transversely extending loadsupport means mounted forwardly of the upright members, upper and lowerroller means mounting the load support means in the upright members forelevation of the load support means in the upright members, said upperroller means being mounted in fixed relation to the load support means,said lower roller means being mounted in movable relation to the loadsupport means, pivotable crank means mounted adjacent the lower rollermeans and in fixed mounting relation to the load support means, andmeans operatively connected to the crank means for elevating the loadsupport means in the upright members, said latter means underpredetermined load effecting pivotal movement of said crank means whicheffects movement of the lower roller means relative to the load supportmeans.

14. A load carrier and upright mast assembly for lift trucks comprisinga pair of laterally spaced upright members supported from the lifttruck, load support means mounted in the upright members for elevationforwardly thereof, laterally spaced pairs of upper and lower rollermeans connecting the load support means to the upright members,pivotable means connected to the load support means and to the lowerrollers in axially spaced eccentric relation, the axis of said pivotablemeans being at a fixed distance from the axis of the upper rollers andfrom the axis of the lower rollers, and load support lifting meansoperatively connected to the pivotable means for actuating same under apredetermined load on the lifting means, such actuation effecting alengthening of the distance between the axes of the upper and lowerroller means.

15. An assembly as claimed in claim 14 wherein actuation of thepivotable means effects downward movement of the lower roller meansrelative to the upper roller means and against the upright memberscausing arcuate movement of the lower end of the load support meansforwardly of the upright members.

16. An assembly as claimed in claim 14 wherein stop and movementlimiting means are associated with the pivot means for limiting therange of pivotal movement thereof in either direction.

17. A load carrier and upright mast assembly for lift trucks comprisinga pair of laterally spaced upright members supported from the truck,load support means mounted for vertical movement in the upright membersforwardly thereof, hoist motor means mounted in the upright member andoperatively connected to the load support means for elevating same inthe upright members, upper and lower pairs of roller means supportingthe load support means in the upright members, said upper roller meansbeing mounted in fixed axial relation to the load support means, a pairof crank means mounted transversely inwardly of the lower roller meansand in fixed axial relation to the load support means, said crank meansextending forwardly of its axis, a transverse member interconnecting theforwardly extending end portions of the crank means, spring meanssecured to the load support means and mounted upon the transverse memberfor urging same downwardly with the end portions of the pair of crankmeans, said hoist motor means being also operatively connected to thetransverse member for urging same upwardly with the crank means inopposition to the spring means, movement limiting means pivotable withthe crank means for limiting pivotal movement thereof in at least onedirection, said lower roller means being mounted upon said movementlimiting means in spaced relation to the axis of the crank means,pivotable movement of the crank means effecting substantially verticalmovement of the lower roller means, said spring means being adapted tomaintain said crank means and transverse members in a downward locationrelative to the load support means until such time as an opposinglifting force applied by the hoist motor means under a load disposed onthe load support means actuates the transverse member upwardly andpivots the crank means.

18. A load carrier and upright mast assembly for lift trucks comprisinga pair of laterally spaced upright members supported from the truck,load support means mounted for vertical movement in the upright membersincluding upper and lower roller means engaging forwardly and rearwardlydisposed portions of the upright members respectively, a portion of therearwardly disposed portion of the upright members being inclined at anangle to the vertical whereby to effect forward tilting of a loadsupport means during vertical movement thereof in said inclined portionof the upright members, and means operatively connected to said lowerroller means and to said load support means for actuating the lowerroller means in a manner to efiect actuation of the load support meansto a reverse tilt position about the axis of the upper roller means uponlifting of the load support means in the upright members underpredetermined load.

References Cited in the file of this patent UNITED STATES PATENTS1,912,816 Anthony June 6, 1933 1,975,252 Clark Oct. 2, 1934 2,569,053Healy Sept. 25, 1 1 2,899,093 Morrell Aug. 11, 1959

1. A LOAD CARRIER FOR LIFT TRUCKS COMPRISING LOAD SUPPORT MEANS, A PAIROF TRANSVERSELY SPACED MEMBERS SECURED TO THE LOAD SUPPORT MEANS, ACRANK ARM MOUNTED IN EACH SAID MEMBER FOR PIVOTAL MOVEMENT RELATIVETHERETO, MEANS INTERCONNECTING SAID CRANK ARMS, RESILIENT MEANS SECUREDTO THE LOAD SUPPORT MEANS AND CONNECTED TO SAID INTERCONNECTING MEANSFOR URGING THE CRANK ARMS IN PIVOTAL MOVEMENT IN A DIRECTION AWAY FROMTHE CONNECTION OF THE RESILIENT MEANS TO THE LOAD SUPPORT MEANS, ANDLOAD LIFTING MEANS OPERATIVELY CONNECTED TO THE CRANK ARMS FOR LIFTINGTHE LOAD CARRIER AND PIVOTING THE CRANK ARMS IN A DIRECTION OPPOSED TOTHE URGING OF THE RESILIENT MEANS WHEN THE LOAD CARRIER SUPPORTS APREDETERMINED LOAD.